“This was not something he planned out,” said Special Agent Tom Simon, an FBI spokesman in Honolulu. “My impression is that he ran for the first flight he saw.”

The 16-year-old was running away from his home in Santa Clara, Calif., and scaled a perimeter fence at San Jose International Airport early Sunday before entering a wheel well of a Hawaiian Airlines Boeing 767, authorities said.

In skipping charges, agents may have decided the boy has suffered enough. The wheel well of the jet is not pressurized or heated, meaning the teen possibly endured extremely thin air and temperatures as low as 80 degrees below zero when the plane cruised at 38,000 feet.

At that altitude, the outside air temperature is about 85 degrees below zero. He lost consciousness during the flight, officials said.

The plane landed at the Maui airport at 10:30 a.m. local time on Sunday, but Simon said the teen did not regain consciousness until an hour later. Once he woke up, he hopped down to the tarmac.

Hawaiian Airlines personnel noticed the teen on a ramp and notified security.

There was no indication that the boy posed a threat to the airline, and he has not been charged with a crime, officials said. He cleared a medical checkup and was handed over to officials from the Hawaii Department of Human Services.

Officials did not release his name because he is a minor.

The boy’s older sister disputed reports that he ran away from home because of a fight.

The San Jose airport, meanwhile, defended its security.

“No system is 100 percent, and it is possible to scale an airport fence line, especially under cover of darkness, and remain undetected,” spokeswoman Rosemary Barnes said.

“SJC’s security program meets and exceeds all federal requirements, and we have an excellent track record,” she said. “We work closely with TSA . . . to secure airport property.”

Critics weren’t buying it.

“I have long been concerned about security at our airport perimeters,” Rep. Eric Swalwell, a Democrat who represents the San Francisco Bay Area, tweeted. “#Stowaway teen demonstrates vulnerabilities that need to be addressed.”

I have long been concerned about security at our airport perimeters. #Stowaway teen demonstrates vulnerabilities that need to be addressed.

According to the FAA, the last known incident in which a stowaway survived a flight was in August 2013 on a flight within Nigeria. Since 1947, the FAA has recorded 94 stowaway incidents; of those, 25 survived.